The present invention relates to a method for producing a single crystal by forming a nucleus, which is a macro-crystal grain, in a part of a polycrystal showing a discontinuous crystal grain growth and growing the nucleus through a solid phase reaction to grow a single crystal.
Heretofore, methods wherein a starting material is melted at a temperature higher than a melting point of the starting material and a single crystal is grown from the molten liquid phase, such as a pick up process, Bernoulli process, Bridgman process, floating zone melting process, flux process and the like have been broadly known.
However, any conventional method wherein a single crystal is grown from the molten liquid phase needs a high temperature, so that when a starting material containing a component having a high vapor pressure is used, the composition readily varies and impurities are readily admixed from a crucible used for melting the starting materials, so that the crystallinity of the obtained single crystal is not uniform. Furthermore, all the above described conventional methods need a large, expensive, complicated production apparatus and severe production conditions. Thus, mass production is difficult and therefore the obtained single crystal product has a high cost.